The present invention relates to light colored homogeneous and aqueous alpha olefin sulfonate solutions. More particularly, it relates to light colored aqueous alpha olefin sulfonate solutions which are free from the occurrence of turbidity therein even when they are allowed to stand for a long period of time.
In general, aqueous alpha olefin sulfonate solutions (which will be referred to as "AOS solutions" for short hereinafter) are manufactured by sulfonating alpha olefins with sulfur trioxide/inert diluent mixture, neutralizing the resulting sulfonated products with alkali solutions such as an aqueous sodium hydroxide solution, and further hydrolyzing the same in the presence of alkali. However, since the reaction between alpha olefins and sulfur trioxide is rapid in nature, it is customary for the AOS solutions obtained according to the above-mentioned method to be colored considerably. Despite this, light colored AOS solutions can be obtained by either employing relatively mild reaction conditions for the sulfonation or subjecting the colored AOS solutions to a bleaching treatment. Employment of the method disclosed, for instance, in Japanese Patent Publication No. 48409/1974 permits the production of light colored AOS solutions without an additional bleaching treatment.
However, it is to be noted that the light colored AOS solutions prepared under mild sulfonation conditions are superior in respect of their quality as surface active agents in comparison with the AOS solutions prepared using a bleaching treatment, but on the other hand they are defective in that turbidity occurs during storage and in an extreme instance the solutions are divided into two phases. The occurrence of turbidity or phase separation as mentioned above inevitably not only proves an obstacle to the storage and handling of the AOS solutions but also deteriorates the commercial value of the AOS solutions per se. Therefore, it is inevitably necessary to prevent the occurrence of such phenomena as mentioned above.